This invention relates to an ice making machine and, more particularly, to a so-called open-cell type ice making machine with its ice making mold provided with a plurality of ice-making cells each of which is opened at the bottom and closed at the top.
The ice making machine of this type is shown by way of example in FIG. 1 and comprised of an ice making mold 1, a water tank 11 disposed therebelow, an ice stocker 12 disposed close to said water tank 11, and an inclined plate 7 positioned intermediate said ice making mold 1 and the water tank 11 and having a downward gradient towards ice stocker 12. The ice making mold 1 has a soup plate-like member 5 having a large number of through-holes, ice making cups 2 engaged in inverted position in said through-holes, said cups defining ice making cells closed at the top and opened at the bottom, and an evaporator 3 in the form of a heat exchange tube in heat exchange relation with ice making cups 2. The inclined plate 7 has water spray openings 8 to permit water to be sprayed into said ice making cells 4 from a plurality of spray nozzles 10a of a water spray tube 10 mounted below inclined plate 7 (only one spray nozzle 10a being shown in the drawing). The plate 7 also has water recovery openings 9 to permit recovery into water tank 11 of return water that has been sprayed into said ice making cells but descended unfrozen onto the inclined plate 7. Water is supplied to the water spray tube 10 by a water circulating pump 11a associated with water tank 11.
In such ice making machine, prior to starting ice making cycle of operation, a water valve WV provided to a water supply tube 6 is opened for supplying water to a cavity 5b of the soup plate-like member 5. The water thus supplied descends onto inclined plate 7 through an opening 5a in the bottom of the soup plate-like member 5 to descende further therefrom into water tank 11 through recovery openings 9 of the inclined plate 7. When the water in water tank 11 has attained a predetermined level, water valve WV is closed for driving water circulating pump 11a and a refrigerating system including said evaporator 3 into operation. This initiates the ice making operation so that the ice making cups 2 are cooled by the evaporator 3, while the ice making water is sprayed from spray nozzles 10a into the thus cooled ice making cups 2. Thus, an ice cube is grown gradually in each ice making cell 4. The unfrozen water descends onto inclined plate 7 as mentioned hereinabove.
When the ice cube has grown to a predetermined size, such state is sensed by a known ice making sensor which then causes cessation of the ice making operation and start of the ice harvesting operation. In such ice havesting operation, water valve WV is again opened to supply water to cavity 5b of soup plate-like member 5, while simultaneously a hot gas valve, not shown, of the refrigerating system is opened for supplying a hot gas into evaporator 3. The result is that ice cubes formed in the ice making cells 4 are removed from ice making cups 2 and descend onto inclined plate 7 to slide down thereon to be stocked in ice stocker 12.
The inclined plate 7 is a flat thin plate in which are punched rectangular openings 9 in staggered relation as shown in FIG. 1A. Hence so far as ice cubes are concerned, they tend to be caught in the openings 9 in the inclined plate 7. When this occurs, the cube ice 4a thus caught in the openings 9 is melted gradually to be seated firmly in the openings 9 (FIG. 1B) to interfere with travel of the following ice cubes sliding down towards ice stocker 12. So far as return water is concerned, return water flowing through a ligament zone 7a between adjoining openings 9 tends to bypass the downstream side opening 9a and be deviated into two streams as shown at a, b in FIG. 1A or to skip over the opening 9a as shown at c in FIG. 1A. The result is that return water flowing further down tends to be spurted out of water tank 11. In addition, return water will flow down through water spray opening 8 to be impinged on a jet opening of each spray nozzle 10a, thus disturbing the flow of spray water from the jet opening and abstructing smooth water spraying to the ice making cells 4 to make it difficult to procure ice cubes of uniform size.
Hence, there is a strong demand for an ice making machine which avoids the aforementioned deficiency and provides an ice making machine whereby return water on the inclined plate may be positively recovered into water tank, the ice cubes may slide down smoothly on the inclined plate and return water does not disturb the flow of spray water from water spray nozzle.